Speciation in the sub‐Antarctic weevil genus Dusmoecetes Jeannel (Coleoptera: Curculionidae)

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Abstract
Relatively few instances of sympatric speciation have been reported in the literature, and both theoretical and empirical studies of this mode of speciation remain controversial. Recently, a model of sympatric speciation less restrictive than earlier ones has been proposed. This study presents a hypothetical speciation scenario, based on current observations, which seems to be consistent with the new model. Two morphologically similar, though ecologically separated, species are identified in the Dusmoecetes similis (C. O. Waterhouse) species complex on Marion Island (46° 54′S, 37° 45′E), based on a study of the morphology, biology and ecology of the group. Differences between the demands placed on angiosperm‐ and bryophyte‐feeding members of the complex, and the differing demands of bryophyte and angiosperm‐dominated communities, coupled with low vagility and a high degree of assortative mating, suggest that a sympatric model can be used to explain speciation in this genus, which probably occurred within the last 10,000 years. Differences between Dusmoecetes marioni Jeannel and D. Similis (Waterhouse) are discussed, and a lectotype designated for the latter species.